Needle assembly and method of producing said assembly



Jan. 12, 1954 w. F. BUTLER NEEDLE ASSEMBLY AND METHOD OF PRODUCING SAIDASSEMBLY Filed "July 3, 1951 INVENTOR. ZU/LL/AM E 19072:?

HTTOP/VEXI Patented Jan. 12, 1954 NEEDLE ASSEIVIBLY AND METHOD OFPRODUCING SAID ASSEMBLY William F. Butler, Oakland, Calif., assignor toCutter Laboratories, Berkeley, Calif., a corporation of CaliforniaApplication July 3, 1951, Serial No. 235,051

1 Claim. 1

This invention relates to hollow needle assemblies for use in takingblood from a donor and for establishing communication between theinterior and exterior of an intravenous solution flask.

Presently, needle assemblies of this character consist of a hollowneedle or cannula bonded to a metal hub to which the usual elastomertubing is connected and which serves as a finger grip for manipulatingthe device. The connection between the cannula and hub must be airtightfor frequently the device is used in conjunction with a partiallyevacuated flask. The assembly must be fairly rugged for the needlesometimes has to be forced through a substantial length of rubberstopper.

In general the object of this invention is the provision of a needleassembly fulfilling the above conditions and which also can be made at aprice sufliciently low to permit of its being thrown away after itsfirst use so as to avoid the inconvenience and cost of sterilizing itfor further use and the danger of improper sterilization.

More specifically, the object of this invention is the provision of aneedle assembly including a metal cannula having a roughened outersurface and a plastic hub molded thereto in airtight sealing engagementtherewith.

The invention possesses other advantageous features, some of which, withthe foregoing, will be set forth at length in the following descriptionwhere that form of the invention which has been selected forillustration in the drawings accompanying and forming a part of thespecification is outlined in full.

In said drawings, two forms of the invention are shown, but it is to beunderstood that it is not limited to such forms, since the invention asset forth in the claim may be embodied in other forms.

Referring to the drawings:

Fig. 1 is a plan view of a pair of needle assemblies attached to theopposite ends of a section of elastomer tubing and each embodying theobjects of my invention.

Fig. 2 is an axial mid-section taken through the lower of the two needleassemblies illustrated in Fig. 1.

assemblies includes a hollow stainless steel or cannula needle I havinga beveled point 2 and an extended sandblasted peripheral surface 3.Molded to the sandblasted portion of the cannula I is a plastic(polystyrene) hub 4 provided intermediate its ends with a radial flange5 and a formed inner end with a counterbore or recess 6. As illustratedin Fig. 1 the inner recessed end of each assembly is connected to asection of elastomer tubing 1. The only difference between the twoassemblies illustrated resides in the flanges 5, the flange of upperassembly being somewhat larger than the lower assembly and slightlydished.

Contrary to the expectations of those skilled in the art I have foundthat the surface of a stainless steel cannula can be roughedsufliciently by sandblasting or by acid etching to enable an air-tightseal to be made between the cannula and a plastic hub molded thereto andto provide a bond strength of greater than 40 pounds of axial force.

As a result of this expedient, my assignee, Cutter Laboratories, is nowable to market needle assemblies having plastic hubs at a pricepermitting of their disposal once they have been used and thereforeobviating the sterilization required of the more costly all-metalassemblies.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

A needle assembly comprising: a stainless steel cannula having asandblasted outer surface portion; and a plastic hub molded around saidcannula about said sandblasted outer surface portion, said hub beingformed with a radially extending flange intermediate its ends.

WILLIAM F. BUTLER.

References Cited in the file of this patent UNITED STATES PATENTS Number

